Biomechanical influence of plate configurations on mandible subcondylar fracture fixation: a finite element study

Abstract

Mandible subcondylar fractures have very high complication rate, yet there is no consensus in a suitable plate design for optimal patient outcomes. The present study is aimed at understanding the subcondylar fracture fixation by comparing load transfer in intact and reconstructed fractured mandibles with five different plates: single mini, trapezoid, lambda, strut, and double-mini plates under the complete mastication cycle. Under contralateral molar occlusion (LMOL), the single mini plate resulted in the highest strains. On the contrary, during ipsilateral molar clenching (RMOL), the tensile and compressive strain distributions were found to be reversed, with the tensile strains at the posterior border resulting in lesser strain in reconstructed mandible with single mini plate. Owing to the reduced strains in the reconstructed mandibles, the contralateral molar clenching task is preferred during the immediate post-surgery period for patients. Under this contralateral molar clenching, the peak von Mises stresses in the plate decreased with increase in the number of screws. Furthermore, the presence of two arms seems beneficial to neutralise the tensile and compressive strains across load cases. Consequently, double mini and trapezoid plates were found to perform better as compared to single mini plate during the entire mastication cycle for subcondylar fracture fixation.